1. Field of the Invention
The present invention relates to a device for transmitting information between a plurality of elements of an automobile vehicle, and a central information processing unit.
2. Background Art
A number of transmitting devices of this type are already known in the art.
Thus, for example, transmitting devices are known which comprise a central information processing unit connected to the various elements of the vehicle through one or more selective access buses, also termed bus of the polling type ensuring the transmission of the information.
The central unit effects a successive polling of all the elements, for example the control elements of the vehicle such as the elements controlling the horn, the direction-changing indicators, etc..., and in response to the controls actuates the corresponding receiving elements.
For reasons of safety of operation, it is necessary to ensure a redundancy of the transmission of the items of information between the control elements and the central unit and between the central unit and the corresponding receiving elements. There have consequently been developed information transmitting systems operating in a differential manner, these systems comprising capacitive coupling mechanisms to permit a sufficient operation of the latter even when one of the data transmission lines is disturbed.
Moreover, it is also desirable to be in a position to operate at transmission frequencies which are as low as possible so as to avoid risks of generation of electromagnetic interferences and to reduce the cost of manufacture of such systems.
These devices have a number of drawbacks, in particular as concerns the selectivity of the priorities of the control elements and therefore of the actions resulting therefrom.
Indeed, there are, in an automobile vehicle, control elements ensuring functions having high priority access characteristics, such as for example the elements controlling the brake, to which the device must immediately react for reasons of safety, and control elements such as for example elements for controlling the window glass raiser, etc... which ensure functions having a low priority access characteristic.
In the known devices, employing for example selective access information transmitting buses, all the control elements are interrogated one after the other and there is therefore no priority access to the central unit.